Occlusively applied anesthetic patch

ABSTRACT

An adhesively applied patch for topical application to intact skin for producing effective anesthesia for varying amounts of time depending upon the extent of time the patch is applied. The patch includes an occlusive member mounted on an adhesive backing, the topical anesthetic agent being on a gauze-like pad received within the occlusive member such that penetration of the anesthetic agent into intact skin is enhanced. The anesthetic agent is preferably the amino-acyl amide type and virtually nonallergenic. Typical uses of such a patch are intradermal allergen skin testing, lunbar punctures, skin biopsies and minor surgical procedures.

United States Patent 1191 Lubens June 4,1974

1 1 OCCLUSIVELY APPLIED ANESTHETIC PATCH [76] Inventor: Herman Michael Lubens, 396 Elm Grove Dr., Dayton, Ohio 45415 UNITED STATES PATENTS 1,643,926 9/1927 Dickson 128/268- 1,861,530 6/1932 Hayden et 211..

3,624,224 11/1971 Wei. 128/156 X OTHER PUBLICATIONS Annals Of Allergy, V01. 22, Pages 37-41 Primary Examiner-Aldrich F. Medbery Attorney. Agent, or Firm-Biebe1, French & Bugg 5 7] ABSTRACT An adhesively applied patch for topical application to intact skin for producing effective anesthesia for varying amounts of time depending upon the extent of time the patch is applied. The patch includes an occlusive member mounted on an adhesive backing, the topical anesthetic agent being on a gauze-like pad received within the occlusive member such that penetra- -tion of theanesthetic agent into intact skin is enhanced. The anesthetic agent is preferably the amino- 1,920,808 8/1933 Sunder 128/ 154 acyl amide type and virtually nonallergnic. Typical 2,029,260 l/l936 Eustis ct a1. 128/268 X uses of such a patch are intradermal allergen skin l t- 2,344,021 BOUZlflIIC ing lunbar punctures kin biopsies and minor urgical 2,579,403 12/1951 Slomowitz et a1. 128/268 procedures 9 3,062,210 11/1962 Scholl 128/156 3,212,495 10/1965 Osbourn et a1. 128/2 7 Claims, 8 Drawing Figures 1 1 OCCLUSIVELY APPLIED ANESTHETIC PATCH BACKGROUND OF THE INVENTION This invention relates to an anesthetic patch and more particularly to an improved occlusive anesthetic patch for producing analgesia in intact skin.

It is well known that most people and substantially all children are acutely sensitive to the pain sensation related to medical procedures associated with the skin surface. Typical such procedures involving the fear of pain include vaccination, immunizations, injections of various types, skinbiopsies, surgical procedures such as removal of cysts, moles, skin lesions, derma-abrasion for scars, needle punctures, allergen skin tests, venipuncture, and the like. The obvious needle phobia and associated apprehension and anxiety is a real factor in medical treatment of some patients. Children fear such injections, whereas adults endure them. Despite the apprehensions of both children and adults, essentially nothing has been done to alleviate the pain sensation caused by needle injections. Hence, there is a substantial need for effective means of quickly, efficiently and temporarily insensitizing intact skin to pain.

DESCRIPTION OF THE PRIORART It is known from Annals of Allergy, Volume 22, pages 37-41, January I964 that patches are useable to produce anesthesia in intack skin. The anesthetic agent there described includes 30 percent .Xylocain. There is no disclosure of an occlusive product, as herein described.

SUMMARY OF THE INVENTION The present invention is directed to an improved skin patch which quickly and efficiently anesthetizes intack skin and abolishes the pain incident to various medical procedures suchas needle injections. In general, the invention provides for pressing a pad of gauze-like material saturated with an anesthetic agent against the intact skin for the purpose of producing anesthesia in intact skin.

In accordance with the invention, the skin patch is sandwiched against an adhesive tape or other skin adhcrent material and includes an occlusive member, generally' annular in shape and which is raised. Received within the occlusive member is a guaze-like pad saturated with an anesthetic agent, the adhesive backing operating to hold the gauze pad in place.

When the patch is applied to intact skin, the occlusive member is effectively sealed to the skin tending to press the gauze pad and the anesthetic agent against the skin for the purpose of increasing the rate of penetration of the anesthetic agent into the skin. In the preferred embodiment. the peripheral edge portions of the gauze pad are coated or impregnated with a blue skin coloring material which is transferred to the skin and which provides a frame-like outline of the skin area under anethesia, once the patch is removed.

The basic concept of the invention may be utilized in a multiple patch, wherein a plurality ofthe patches are sandwiched between a large sheet of skin adherent material and a large sheet of overlying protective material, for example for use in intradermal allergen skin testing. Additionally, the large sheets of base material and overlying material may be perforated so that a unitary patch may be separated one at a time. Another form of the invention, which facilitates dispensing of such patches, includes a continuous strip in convoluted roll form of plastic overlying material enclosing individual sections of separable patches.

DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of an occlusively applied anesthetic skin patch constructed according to the present invention;

FIG. 2 is an exploded view of the skin patch of FIG.

FIG. 3 is across-sectional view of the skin patch of FIG. 1 applied to intact skin;

FIG. 4is a perspective view of a multiple patch having a plurality of skin patches sandwiched between a thin plastic overlying sheet and a large strip of tape skin adherent;

FIG. 5 is an exploded view showing a plurality of skin patches applied to perforated pieces of skin adherent and protected by a perforated overlying sheet of thin plastic material;

FIG. 6 is a perspective view showing a roll of individualized skin patches applied to a continuous strip of overlying plastic material;

FIG. 7 is a schematic view of a multiple patch applied to the upper arm of an individual; and

FIG. 8 is a schematic view of the upper arm of FIG. 7 after the multiple patch has been removed, and showing the multiple anesthetized sites framed by marking material transferred onto the upper arm by the patch material.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, the anesthetic skin patch 10 of the present invention comprises occlusive means consisting of an annular resilient member 12 adhered to an adhesive coated backing member 14 to form therewith a shallow cup-like space. That portion 16 of the adhesive member 14 overlying the occlusive member 12 is impermeable. The adhesive member 14 is larger insurface area than the occlusive member 12 so that when the patch 10 is applied to the skin (FIG. 3), the occlusive member 12 is held firmly in contact and effectively seals against the skin.

Received within the occlusive member 12 and adhered to that portion 16 of the adhesive member 14 is a pad of gauze-like material 25 (FIG. 2).- The gauzelike pad 25 is preferably a porous gauze material capable of absorbing a liquid or cream anesthetic for topically anesthetizing intact skin. The peripheral edges 29 of the gauze pad 25 are preferably marked with a blue skin marking crayon (cross-hatching) so that, after the pad is removed to the skin, the anesthetized site will be quickly apparent.

Lidocaine. also known as Xylocaine, and having the chemical name 2-di ethylar nino-2 o -aceto-xylidide. is a useful topical infiltration, nerve block, spinal, peri dural and caudal anesthetic. It is particularly useful in connection with the present invention, because a 10 --50 percent Lidocaine cream formulation is useful in inducing anesthesia in intack skin. A 30 percent Lidocaine cream formulation, for example, will anesthetize adjacent skin when in contact for twenty to thirty minutes. A typical such formulation contains the following constituents:

Lidocaine Cetyl Alcohol Spermaceti Beeswax White Petrolatum Liquid Petrolatum Glycerine Methyl Paraben Sodium Lauryl Sulfate Aluminum Acetate Dionized Water q.s.

The occlusive member 12 and guaze pad 25 are so proportioned that when the patch is applied to the intact skin (FIG. 3), by adhesive member 14, the occlusive member 12 is pressed against the skin, and the gauze-like pad is pressed against the skin which action increases the rate of skin penetration by the anesthetic agent within the pad. Consequently, the intact skin is insensitized more quickly than has heretofore been possible.

This effectiveness of the anesthetic patch depends on (1) high concentration percent Lidocaine, (2) a suitable vehicle, (3) an adequate period of application (30 minutes or more), and (4) an occlusive dressing. The gauge piecafiay be in varToussiEs and shapes as required'for the contemplated procedure. Before application to the desired intack skin area, the area is cleansed with acetone and alcohol. In one form the gauze on the anesthetic patch is saturated with the anesthetic cream. The anesthetic patch is then applied to the intake skin area. The anesthetic patch is removed after the required period of 30 minutes or more at the area where the patch was applied, which is then clearly demarcated by a blue border. This area is completely anesthetized in preparation for a painful procedure.

The invention may be used in a number of advantageous ways. For example, for intradermal allergen skin testing, a plurality of skin patches may be used on a single sheet of skin adherent material. Referring to FIG. 4, a multiple patch 30 has a plurality of skin patches 10 mounted with their recessed ends against a base sheet of skin adherent material such as tape. Each of the skin patches 10 carries a pad saturated with the anesthetic agent, and the edges 36 of each of the pads may be marked with a blue skin coloring marking material. For protective purposes. the multiple patch sheet is covered by a plastic sheet 38 of larger dimension than the sheet 30. If desired, the entire sheet 30 may be sealed in a sterile package. as is known in the art. In other forms, the anesthetic agent may be applied to the gauze pad, and the assembly packaged, or the anesthetic agent may be packaged separately and applied to the gauze immediately before use.

Referring to FIGS. 7-8, after the plastic layer 38 is removed, the multiple patch 30 may be applied to the skin for intradermal allergen testing (FIG. 7). The base layer 35 carries the occlusive member and gauze and holds the patch 30 on the skin. After a period of approximately l0 minutes, the multiple patch 35 may be removed (FIG. 8) to reveal the blue skin marking material on the edges of each pad, which is transferred to the skin and forms a series of blue frame-like marks indicating the spots where the anesthetic agent has been applied to the intact skin. It is therefore within these marks where the doctor performs his allergen testing without causing pain to the patient.

In another embodiment of the present invention (FIG. 5), a perforated base sheet 40 of skin adherent" material such as tape forms a plurality of generally square or rectangular sections, and each section includes a skin patch 10. An overlying sheet of correspondingly perforated plastic material 41 is then placed over the base sheet 40 in position such that individual patches 10 may be separated one at a time by tearing along the perforations. In still another embodiment (FIG. 6), thin patches 10 on individualized rectangular pieces of tape 45 are mounted on a continuous strip or roll 46 of plastic material. In this form, individual patches 10 may be separated by severing them from the roll 46.

The multiple type of anesthetic patch is used primarily for allergen intradermal skin testing. The gauze squares are by inch in area. A strip of elastic adhesive base material, 3 inches wide by 7 inches long contains two vertical rows of five of these squares 1 inch apart. Each of the 10 small gauze areas is saturated with the anesthetic cream before application to the skin. The multiple patch is then applied to the upper arms or upper back depending upon the age of the patient (in small children up to the age of approximately 6 years the back is used.) The application of two multiple anesthetic patches thus produces four rows of five anesthetized demarcated skin testing areas each or 20 sites for allergen intradermal skin testing.

Solitary patches consist of larger gauze squares demarcated with blue skin marking crayon placed on the adhesive base material of appropriate size depending upon the procedure to be performed. These solitary patches are made 1 inch square to 2 inches square or larger. For a needle puncture, such as an injection, or venipuncture, one can use a small anesthetic patch for lumbar punctures, a larger one is used as a 2 inch square, for minor surgery an anesthetic patch 2 inches square or possible 3 inches or larger can be used.

Actually one can theoretically fashion an anesthetic patch to fit any other suitable anesthesia purpose.

During a period of over 9 years of experimental use of anesthetic patch on human patients approximately 300 ounces of the 30 percent Lidocaine anesthetic cream have been applied to approximately 3,000 patients in the form of over 250,000 patches. There have been no adverse reactions or untoward symptoms at all. Over 5 years ago in a series of ten guinea pigs the 30 percent Lidocaine anesthetic cream was applied to approximately 50 percent of the body surface for a period of over 4 hours. No untoward reactions occurred. During this guinea pig study a 3 inch long scalpel skin incision was made into the dorsal surface of one of the guinea pigs which was then closed by five skin sutures. This operative procedure resulted in no pain experience for the guinea pig, in contrast to a control guinea pig where such a procedure was obviously painful.

The multiple anesthetic patch has been utilized experimentally for a period of over 9 years for the performance of painless intradermal allergy skin testing at the allergy clinic and in private practice. Objectively and subjectivelyit has been observed that the anesthetic patch produces local anesthesia and permits painless skin testing. Women especially are pleased at the absense of pain during skin testing. Some remarked that they had been very anxious about the testing but were happy to find that they were painless. In children the most gratifying results have been observed. Generally speaking the elimination of the pain aspect of skin testing has had a uniformly noticeable effect on the ease of execution of the tests. The most obvious beneficial effect has been the lessened apprehension and anxiety in all concerned. The application of the anesthetic patch produces neatly visible demarcated areas, anesthetized skin for each test allergen. This permits a slow accurate execution of the allergy tests in contrast to the hurried painful application; this latter situation usually producing an atmosphere of tense emotion and confusion in a struggling, crying. frightened child. In addition the psychological suggestive aspect of the pre-injection care of the skin area to be injected by a soothing painless procedure like the anesthetic patch lessens the apprehension of the child. Together these factors thus promote accuracy in skin testing and in many ways alieviate the difficulties in the allergen testing of children. The anesthetic patch adds a scientific aura and dignity to the procedure of allergy skin testing. Incidentally, allergy testing is made easier for inexperienced individuals such as paramedical personnel or others who are not too adept at the procedure. The allergy tests can be done without the necessity of performing them rapidly on a struggling uncomfortable patient.

A series of seven infants were subjected, on an experimental basis. to the application of a large solitary anesthetic patch for 3 hours prior to spinal tap. Excellent anesthesia was produced thus enabling the spinal tap to be done painlessly. In three older children the anesthetic patch similarly was used to the area for a skin punch biopsy for 3 hours. Apparently excellent results were obtained as no child complained of pain.

A series of 18 minor surgical procedures (such as cystsmoles) utilizing the 2 inch solitary patch for complete anesthesia was performed successfully for experimental purposes.

In a large series of children, the anesthetic patch has been used experimentally to provide complete anesthesia for various procedures such as phlebotomies, spinal taps, and injections. Many of these cases require repeated intravenous injections and spinal taps.

ln a large series of cases involving young children who were fearful of the hypodermic subcutaneous injections necessary for hypo-sensitization immunetherapy treatment of allergic diseases, small areas utilizing the small anesthetic patches which make up the multiple anesthetic patch were used on each arm. The mother applied these patches a period of time prior to the office visits where the injections were to be given. This has proved to be very successful in that it eliminates the fear of these injections which children usually have.

Blood donors are a most essential requirement for health care and in the belief that making the blood donation painless this would encourage blood donation, the anesthetic patch was experimentally utilized successfully in small series of cases. The possibility that painless blood donations at a blood bank might encourage many people to give blood and thus raise a significant number of blood donors a year seems very possible.

Lidocaine is an amino-acyl amide, completely unrelated to the other (caine) drugs such as Nupercaine, Procaine, etc. It is virtually nonallergenic. During the past period of over 9 years of continual experimental usage no allergic reactions. skin sensitizations, or other adverse reactions have been observed. The anesthetic patch would seem to have properties of an ideal anesthetic agent. which are considered to be: (1) effectiveness on topical application to the skin; (2) potency for abolition of pain sensation; (3) adequate duration of anesthesia; (4) inability to cause allergenic sensitization; (5) inability to diminish the den'nal response of allergenic skin testing. The anesthetic patch does not alter the skin reactions to allergen testing. Controlled studies showed no appreciable difference in skin test reactions such as 4+, 3+, or otherwise, between anesthetic patch areas and adjacent control areas; (6) freedom from skin irritation; and (7) freedom from side effects.

The duration of the anesthetic effect produced by an anesthetic patch varies with the time of application. If the time of application is 4 hours, the anesthetic effect exists for approximately 3 hours; for 3 hours application time the effect lasts for over an hour and a half; and for 2 hours application time over one-half hour. The anesthesia is profound and very complete.

The anesthetic patch of appropriate type can be applied by the patient at home before going to the clinic, hospital, or office, so that by the time the patient is to be subjected to a painful procedure an anesthetized area has been prepared. This fact may well permit many procedures, especially in children, to be performed in the physicians office rather than requiring hospitalization and other anesthesia. The patient is supplied with a package which contains an alcohol wipe, a small disposal syringe with adequate anesthetic cream, an anesthetic patch and a printed form of instructions for self-application of the patient. In effect, the patient is his own anesthetist.

The anesthetic patch clearly has many advantages over other methods of anesthesia for local painful procedures: (I) no initial pain from needles for local anesthetic or other methods such as freezing sprays: (2) the anesthesia is localized to the exact area require for the procedure; (3) there is no swelling or distortion of the area by infiltration from the localanesthetic solution or other anesthetic agent sprayed on; (4) no adverse side effects can occur from systemic adsorption of a local anesthetic agent. A very prominent advantage is the lessening of the anxiety and fear of the patient during the performance of the painful procedure. A number of cases of marked needle phobia where a stick of the needle would cause syncope on the first effort were found to be ameliorated by the anesthetic patch usage, so that after several visits with the usage of the anesthetic patch the needle phobia remarkably improved.

There are many anticipated areas of utilization of the anesthetic patch which could virtually include any painful procedure to be performed on the intact skin of the body and possibly others. The anesthetic patch may be used for immunization and other injections (diabetics), skin biopsies, minor surgical procedures such as removal of cysts, moles, skin lesions, lumbar punctures, venipunctures, etc.

While the present invention has been described with particular reference to the use of Lidocaine as the active anesthetic agent, other non-allergenic topical anesthetic agents may be used such as Carbocaine or similar anesthetic agents. Penetration of the anesthetic agent through intact skin may also be enhanced by the use of volatile materials such as camphor, menthol, phenol, and a particularly useful formulation has included an anesthetic agent such as Lidocaine or Carbocaine, propylene glycol and dimethylsulfoxide (DSMO). The advantage of volatile materials is the increased penetration through intact skin and the reduction in time needed to achieve effective anesthesia. It will be apparent to those skilled in the art that other modifications may be made in order to achieve the effectiveness of the anesthetic agent within the framework of the present invention.

While the forms of apparatus herein described constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to these precise forms of apparatus, and that changes may be made therein without departing from the scope of the invention.

What is claimed is:

l. An anesthetic patch for topical application to a predetermined area of intact skin of a patient to produce local anesthesia within such area, comprising:

a. a backing member of substantially larger surface dimensions than said area,

b. absorbent pad means of surface dimensions larger than said area but smaller than said backing member positioned on said backing member with an exposed portion of said backing member surrounding said pad means,

c. an anesthetic agent contained in said pad means,

d. occlusive means for securing said pad means in occlusively sealed pressure contact with said area of the patients skin to increase percutaneous penetration of said anesthetic agent into the opposed intact and intradermal skin and adjacent tissue for producing anesthesia thereof, and

e. said occlusive means being constituted in part by the fact that the portion of said backing member overlying and surrounding said pad means is substantially impermeable, in part by the fact that said pad means is of substantial thicknesses, and in part by the provision of an adhesive coating on said surrounding portion of said backing member establishing a continuous ring of scaled engagement between said backing member and the patients skin.

2. An anesthetic patch as defined in claim 1 wherein said occlusive means is also constituted in part by a pressure member secured on said surrounding portion of said backing member outwardly of said pad means and of comparable thickness to but more dense material than said pad means to maintain pressure on skin of the patient adjacent said predetermined area while said pad means with said anesthetic agent therein is maintained in firm contact with said skin area.

3. An anesthetic patch as defined in claim 1. wherein said occlusive means is also constituted in part by an annular member secured on said backing member in surrounding relation with said pad means. the outer dimensions of said annular member being less than said backing member to leave exposed the outer peripheral area of said backing member for adhesive engagement with the skin of the patient, and said annular member being of more dense material than said pad means but being no thicker than said pad means in order to maintain pressure on the skin of the patient surrounding said predetermined area while said pad means with said anesthetic agent thereon is maintained in firm sealed contact with said skin area.

4. An anesthetic patch as defined in claim 1 wherein said pad means comprises gauze, and said anesthetic agent comprises a 30 percent Lidocaine cream formu-- lation.

5. An anesthetic patch as defined in claim 1 wherein said anesthetic agent is a mixture of anesthetic material in a carrier, and wherein said anesthetic material is a nonallergenic anesthetic of the amino-acyl amide type.

6. An anesthetic patch as defined in claim 1 wherein said carrier is a volatile carrier and said anesthetic material is Lidocaine.

7. An anesthetic patch as defined in claim 1 wherein said anesthetic agent is a mixture comprising a nonallergenic anesthetic of the amino-acyl amide type and a carrier comprising dimethylsulfoxide. 

2. An anesthetic patch as defined in claim 1 wherein said occlusive means is also constituted in part by a pressure member secured on said surrounding portion of said backing member outwardly of said pad means and of comparable thickness to but more dense material than said pad means to maintain pressure on skin of the patient adjacent said predetermined area while said pad means with said anesthetic agent therein is maintained in firm contact with said skin area.
 3. An anesthetic patch as defined in claim 1 wherein said occlusive means is also constituted in part by an annular member secured on said backing member in surrounding relation with said pad means, the outer dimensions of said annular member being less than said backing member to leave exposed the outer peripheral area of said backing member for adhesive engagement with the skin of the patient, and said annular member being of more dense material than said pad means but being no thicker than said pad means in order to maintain pressure on the skin of the patient surrounding said predetermined area while said pad means with said anesthetic agent thereon is maintained in firm sealed contact with said skin area.
 4. An anesthetic patch as defined in claim 1 wherein said pad means comprises gauze, and said anesthetic agent comprises a 30 percent Lidocaine cream formulation.
 5. An anesthetic patch as defined in claim 1 wherein said anesthetic agent is a mixture of anesthetic material in a carrier, and wherein said anesthetic material is a nonallergenic anesthetic of the amino-acyl amide type.
 6. An anesthetic patch as defined in claim 1 wherein said carrier is a volatile carrier and said anesthetic material is Lidocaine.
 7. An anesthetic patch as defined in claim 1 wherein said anesthetic agent is a mixture comprising a nonallergenic anesthetic of the amino-acyl amide type and a carrier comprising dimethylsulfoxide. 